Irish police have raided a house as part of the investigation into the killing of constable Ronan Kerr.

Items were seized for forensic examination following searches in Scottstown, Co Monaghan, close to the border with Northern Ireland.

Constable Kerr died when a bomb exploded under his car in Omagh, Co Tyrone, on April 2.

Two men were freed on Tuesday by Northern Ireland detectives investigating the death. A 33-year-old man remains in custody.

A Police Service of Northern Ireland (PSNI) spokesman said: "As part of the ongoing PSNI investigation into the murder of constable Ronan Kerr and a subsequent arms find in Coalisland, a house was searched in Co Monaghan.

"The search was conducted by members of An Garda Siochana, who continue to liaise with detectives investigating both constable Kerr's murder and the Coalisland arms find."

Weapons and explosives were discovered by police in Coalisland. None were seized in Monaghan.

During the house search in Scottstown, a number of items were seized and have been removed for forensic examination. There were no arrests and the investigation continues, officials said.

Constable Kerr, 25, was the victim of dissident republicans opposed to the peace process, though none of the extremist groups has yet claimed responsibility for his killing. It is believed he was targeted because he was a Catholic, with dissidents keen to undermine the cross-community support for the new-look police service that replaced the Royal Ulster Constabulary.

Following the murder, which sparked widespread condemnation, police uncovered the cache of weapons and explosives near Coalisland, Co Tyrone.